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Article
Publication date: 25 February 2014

Lijun Chen and Wei Jiang

Fluorinated polyurethane combines some virtues of polyurethane and fluorinated polymer, such as low water absorption, attractive surface properties, good wearability and…

Abstract

Purpose

Fluorinated polyurethane combines some virtues of polyurethane and fluorinated polymer, such as low water absorption, attractive surface properties, good wearability and high weatherability. Fluorocarbon chains have been incorporated into polyurethanes by fluorinated diisocyanates, chain extenders, polyether glycols, polyester glycols and end-cappers. However, the fluorinated polyurethane, which is prepared with monohydric fluorocarbon alcohol, is seldom reported. The purpose of this research is to prepare and apply the novel fluorocarbon alcohols with side chain to modify polyurethane as the blocking agent.

Design/methodology/approach

The novel fluorocarbon alcohol with side chain 2-methoxy-3-nonene perfluorinated oxygen propanol (MNPOP) can be prepared via alcoholysis reaction of methanol and 2,3-epoxypropyl perfluorinated nonene ether (EPPNE), which was prepared with etherification of hexafluoropropene trimer (HFPT) and 2,3-glycidol. Structures of EPPNE and MNPOP are confirmed with FTIR and NMR. The polyurethane can be modified when MNPOP is used as blocking agent.

Findings

In comparison with the conventional polyurethane, the hydrophobic property of fluorinated polyurethane is improved. However, the increase of tensile strength of modified polyurethane is not obvious because MNPOP belongs to monohydric alcohol. And the function of MNPOP in the modified polyurethane is the blocking agent. The thermal stability of conventional and modified polyurethane is almost the same because MNPOP is de-blocked and fluorocarbon chains have not been incorporated into polyurethanes when the temperature is more than 150°C.

Originality/value

The polyurethane is modified with the novel fluorocarbon alcohols with side chain, which functions as the blocking agent. The hydrophobic property of fluorinated polyurethane is improved.

Details

Pigment & Resin Technology, vol. 43 no. 2
Type: Research Article
ISSN: 0369-9420

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Article
Publication date: 7 November 2016

Tingting Xu, Cuifeng Zhang and Lijun Chen

Presently, a wide range of polyurethane adhesives can be obtained using different kinds of polyols and isocyanates. However, the applied temperature of the polyurethane

Abstract

Purpose

Presently, a wide range of polyurethane adhesives can be obtained using different kinds of polyols and isocyanates. However, the applied temperature of the polyurethane adhesive is not more than 80°C. The film of polyurethane adhesive will be softened and deformed when its applied temperature is more than 100°C. Thus, the mechanical property of the polyurethane adhesive is decreased clearly, which limits its further application. The purpose of the study is to improve the heat resistance of polyols, especially polyester polyols and its resultant polyurethane adhesives.

Design/methodology/approach

The more rigid benzene ring is introduced into the polyester polyols to improve the heat resistance of its resultant polyurethane adhesive.

Findings

The more rigid benzene ring has ben introduced into the polyester polyols and the heat resistance of its resultant polyurethane adhesive is improved.

Originality/value

The polyester polyols with more rigid benzene ring have been prepared successfully by the vacuum melting method when diethylene glycol, neopentyl glycol, 1,6-hexanediol, ethanediol, isophthalic acid, terephthalic acid, sebacic acid and adipic acid are used as raw materials and tetra-isopropyl titanate is adopted as the catalyst.

Details

Pigment & Resin Technology, vol. 45 no. 6
Type: Research Article
ISSN: 0369-9420

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Article
Publication date: 1 May 2002

Subrata Mondal, Jinlian Hu, Zhuohong Yang, Yan Liu and Yau-shan Szeto

Thermal-responsive shape-memory polyurethane consists of two phases, a thermally reversible phase for maintaining a transient shape and fixed phase structure for…

Abstract

Thermal-responsive shape-memory polyurethane consists of two phases, a thermally reversible phase for maintaining a transient shape and fixed phase structure for recovering the original shape. The use of shape memory polyurethane in clothing is a novel concept. The aim of this paper is to introduce the application of shape memory polyurethane to smart clothing, whose thermal insulation value could be change depending on the change of temperature of the external environment to give comfort regardless of weather change. Thus a review on the shape memory polyurethane is introduced: the mechanism of the shape memory polyurethane is described; the difference between ordinary polyurethane and shape memory polyurethane, the research on shape memory polyurethane and its potential application to smart garment are summarized; the work being carried out in the Hong Kong Polytechnic University are also introduced.

Details

Research Journal of Textile and Apparel, vol. 6 no. 2
Type: Research Article
ISSN: 1560-6074

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Article
Publication date: 29 June 2012

A.P. Kabra, P. Mahanwar, V. Shertukde and V. Bambole

The purpose of this paper is to formulate two component polyurethane coatings based on acrylic polyol, to study the effects of variable nanosilica loadings in these…

Abstract

Purpose

The purpose of this paper is to formulate two component polyurethane coatings based on acrylic polyol, to study the effects of variable nanosilica loadings in these coatings on different morphological, optical, mechanical, corrosion resistance and weather resistance properties and to study the intercalation of acrylic polyol molecules into nanosilica crystals by XRD technique.

Design/methodology/approach

Two component polyurethane coatings were synthesised using acrylic polyol and isocyanate HDI. The nanosilica was incorporated in polyurethane formulation at the weight ratios of 1%, 3% and 5% based on total weight of polyol and isocyanate. The performance of nanocoatings was compared for variable loads of nanosilica for different properties such as morphological, optical, mechanical, corrosion resistance, weather resistance and were studied for intercalation of acrylic polyol into nanosilica crystals by XRD technique.

Findings

Improvement in the properties of polyurethane coatings is achieved with the incorporation of nanosilica. The improvement is the result of inherently high properties of inorganic nanosilica. Tensile strength, scratch hardness, abrasion resistance, corrosion and weathering resistance show significant improvement in performance with the incorporation of nanosilica. Properties are found to deteriorate beyond a certain loading of nanosilica; hence it is important to optimise loading level. The optimal range for high performance was found to be in the range of 1% to 3%. The improvement was a result of synergistic behaviour and good interfacial interaction between polyurethane and nanosilica at optimal levels.

Research limitations/implications

The method used for incorporation of nanosilica into polyurethane was direct incorporation method. The other method of incorporation, i.e. in situ addition and its effect on properties can also be studied.

Practical implications

With the addition of optimal loading level of nanosilica to polyurethane coatings, properties can be enhanced up to the mark. The addition is relatively easy and cost effective.

Originality/value

The paper proves the significance of incorporation of nanosilica on original properties of polyurethane coatings and widens the area of applications of two component polyurethane coatings from acrylic polyol by strengthening them in their properties. The coatings can be applicable in high performance topcoats especially for automotive topcoats.

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Article
Publication date: 1 January 2016

Tongyan Pan and Qifeng Yu

This study aims to present the fabrication of the two-layer system, coating it on steel surface and evaluating the system’s anti-corrosion performance using the ASTM…

Abstract

Purpose

This study aims to present the fabrication of the two-layer system, coating it on steel surface and evaluating the system’s anti-corrosion performance using the ASTM Standard Salt-Spray Test: B117 and the technique of Electrochemical Impedance Spectroscopy (EIS).

Design/methodology/approach

A synthesized electroactive polyaniline (PANi) was utilized in this study to make a PANi-based primer, with which a two-layer coating system was fabricated by overlaying the primer with a polyurethane top-coat.

Findings

In the Salt-Spray test, the two-layer PANi/polyurethane system exhibited higher corrosion resistance than the two-layer control epoxy/polyurethane system. In particular, the PANi/polyurethane system tended to mitigate the production of rust on substrate surface and demonstrated higher delamination resistance. The EIS analysis confirmed the high corrosion resistance and delamination resistance of the two-layer PANi/polyurethane system based on parameters obtained using the best-fit equivalent circuits.

Practical implications

The demonstrated anti-corrosion capacity of this new PANi/polyurethane system laid a solid base for industrial applications.

Originality/value

This novel coating system is expected to achieve improved corrosion protection for steels than the conventional zinc-rich three-layer coatings.

Details

Anti-Corrosion Methods and Materials, vol. 63 no. 5
Type: Research Article
ISSN: 0003-5599

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Article
Publication date: 6 July 2010

S. Awasthi and D. Agarwal

The purpose of this paper is to describe how to synthesise polyurethane resins by using different polyester polyols and HDI isocyanurate. The polyester polyols were…

Abstract

Purpose

The purpose of this paper is to describe how to synthesise polyurethane resins by using different polyester polyols and HDI isocyanurate. The polyester polyols were prepared by reacting single diol with different diacids. The effects of these polyester polyols on the performance properties of the coating films are studied.

Design/methodology/approach

A series of hydroxyl‐terminated polyester polyols were synthesised by using 1,4‐cyclohexanedimethanol (1,4‐CHDM) with different diacids such as 1,3‐cyclohexanedicarboxylic acid (1,3‐CHDA), 1,4‐CHDA, adipic acid (AA), azelaic acid (AZA), and isophthalic acid (IPA). The general properties including acid number, hydroxyl number average molecular weight, polydispersity index, and viscosity of these polyester polyols were evaluated. Different coating formulations were developed by using polyester polyols and HDI isocyanurate. These coatings were applied on sand blasted mild steel panels and glass panels and were cured in hot air oven. Various mechanical, thermal and chemical resistance properties of the coating films were evaluated.

Findings

The paper shows that, the polyurethane coatings have good resistance to water and other chemicals and can be used safely in exterior applications. In polyester polyols for polyurethane coating, CHDA showed a good balance in mechanical properties, which may be attributed to its unique cycloaliphatic structure and 1,4‐substitution. The polyester polyol based on aromatic diacids provided polyurethane coatings with maximum hardness and high Tg.

Research limitations/implications

The polyurethane resins were prepared from polyester polyol (made up of cyclohexanedimethanol (CHDM) and CHDA, IPA, AA, and AZA). Besides, this, it can be synthesised from some other polyester polyols (having different acids and alcohols) or polyether polyols. In addition to this, some other isocyanates such as TDI, MDI, HMDI, etc. can also be used.

Practical implications

The paper has provided a better solution for developing high solid polyurethane coatings for exterior applications due to presence of cycloaliphatic compounds.

Originality/value

In this paper, cyclohexyl dibasic acids have been used as the replacement for the aromatic dibasic acids. In aromatic dibasic acids, the phenyl ring readily absorbs UV‐light limiting the photo‐oxidative stability of the polyesters. So, these studies will help to develop high‐solid polyurethane coatings which could find numerous industrial applications in surface coatings.

Details

Pigment & Resin Technology, vol. 39 no. 4
Type: Research Article
ISSN: 0369-9420

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Article
Publication date: 7 November 2016

Lizhu Liu, Weiliang Li, Weiwei Cui, Xiaorui Zhang and Weng Ling

In this paper, boric acid was loaded on the surface of expandable graphite (EG), polyvinyl alcohol (PVA) and silane coupling agent (KH550) served as a bridge. The purpose…

Abstract

Purpose

In this paper, boric acid was loaded on the surface of expandable graphite (EG), polyvinyl alcohol (PVA) and silane coupling agent (KH550) served as a bridge. The purpose of this study was to improve the flame retardant properties of semi-rigid polyurethane, meanwhile, the mechanical properties of the foam got ameliorated.

Design/methodology/approach

PVA was dissolved in hot water. EG was added to this solution. After stirring for 0.5 h at 85°C in ultrasonic agitation, the system was put at room temperature to cool. The silane coupling agent KH550 was added dropwise into the solution system, stirring to fully hydrolyze. Boric acid was added into the system, placing it in an oven at 90°C to dry after filtration. Changing of flame retardant properties and mechanical properties of semi-rigid polyurethane adding modified EG were characterized.

Findings

The flame retardant performance of the foam with EG has been improved, whereas the tensile strength decreased with an increase in the content of EG. After adding modified EG, compared to semi-rigid polyurethane with EG, flame retardant performance and tensile strength of the foam improved.

Research limitations/implications

In the study reported here, the surface of EG was modified by boric acid. The modified EG was added into semi-rigid polyurethane foam. The flame retardant performance and tensile strength of the foam after adding modified EG were discussed. Results of this research could benefit in-depth study of the influence of adding modified EG to semi-rigid polyurethane. The study could promote the application of flame-retardant polyurethane foam.

Originality/value

The flame retardant performance and tensile strength of the semi-rigid polyurethane were improved by adding modified EG. The effects of modified EG on the flame retardant performance and tensile strength of semi-rigid polyurethane were discussed in detail.

Details

Pigment & Resin Technology, vol. 45 no. 6
Type: Research Article
ISSN: 0369-9420

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Article
Publication date: 1 July 2014

Yanhua Zhang, Jun Cao, Haiyan Tan and Jiyou Gu

The mechanisms of the deblocking reaction of the polyurethane with blocking agent were investigated in detail relatively using thermogravimetric analysis (TGA), Fourier…

Abstract

Purpose

The mechanisms of the deblocking reaction of the polyurethane with blocking agent were investigated in detail relatively using thermogravimetric analysis (TGA), Fourier transform infrared spectrometry (FTIR) and X-ray photoelectron spectroscopy (XPS). This kind of method for polyurethane as the application of wood adhesives can provide the conditions of application and the main theoretical basis.

Design/methodology/approach

The blocking rate and latex particle size distribution were determined using the titrimetric analysis and the laser particle analysis, respectively. TGA, FTIR, XPS and differential scanning calorimetry were used to investigate the deblocking temperature and time of the blocked isocyanate in detail.

Findings

The results indicated that the blocking rate was approximately 97 per cent and the average particle size was 360 nm. The results of laser particle analysis have confirmed that the dispersivity of the blocked polyurethane emulsion was good. XPS results showed that the amount of –O = C-N-benzyl groups increased with an increasing deblocking temperature and subsequently reached equilibrium. In summary, the blocked isocyanate was deblocked at temperatures ranging from 50 to 90°C.

Research limitations/implications

An important approach in future wood adhesive work would be to gain access to man-made board application data.

Practical implications

The paper provided some useful information about deblocking mechanisms of blocked polyurethane that would be helpful to guide applied practical applications as wood adhesive.

Social implications

To promote China’s wood processing technology progress and solve the problem of shortage of the natural quality of wood is of important practical significance.

Originality/value

The paper is the first to use the XPS characterisation method to characterise deblocking polyurethane solution.

Details

Pigment & Resin Technology, vol. 43 no. 4
Type: Research Article
ISSN: 0369-9420

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Article
Publication date: 7 November 2016

Zulfiqar Ali Raza, Aisha Rehman and Rashid Masood

The purpose of this study was to overcome discomfort associated with it, a resin finish was applied in conjunction with hydrophilic polyurethane.

Abstract

Purpose

The purpose of this study was to overcome discomfort associated with it, a resin finish was applied in conjunction with hydrophilic polyurethane.

Design/methodology/approach

The process variables included concentrations of polyurethane and resin finishes, and pH under central composite design (CCD). The fabric specimens were assessed for crease recovery angle (CRA), tensile strength and moisture management properties.

Findings

Some models were developed for prediction of CRA and overall moisture management capability (OMMC) of treated fabric. It was observed that polyurethane concentration showed a parabolic relationship with CRA and a direct relationship with OMMC, whereas resin concentration showed a parabolic relationship with CRA and an inverse relationship with OMMC. Increase in pH from acidic to alkaline resulted in a decrease in CRA but an increase in OMMC. The untreated specimen had the highest tensile strength, whereas the specimen treated with polyurethane showed the least tensile strength loss, and the one treated with resin showed the highest loss in tensile strength.

Practical implications

As the polyurethane-based finish is soft and hydrophilic, so it was expected that it would overcome the uncomfortable feature of durable press finish, and with its flexibility, the strength losses might reduce.

Originality/value

This is the first report about the investigation of effects of increasing flexibility of the cross-link by incorporating polyurethane compounds into a typical dimethylol dihydroxy ethylene urea durable press resin formulation.

Details

Pigment & Resin Technology, vol. 45 no. 6
Type: Research Article
ISSN: 0369-9420

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Article
Publication date: 27 March 2007

S. Dutta and N. Karak

To evaluate the performance of the blends of Mesua ferrea L. seed oil based polyurethane resins with a commercially available bisphenol‐A epoxy resin at different weight ratios.

Abstract

Purpose

To evaluate the performance of the blends of Mesua ferrea L. seed oil based polyurethane resins with a commercially available bisphenol‐A epoxy resin at different weight ratios.

Design/methodology/approach

For effective improvement of their various properties, polyurethane‐ester (PE) and polyurethane‐amide (PA) resins of Mesua ferrea L. seed oil were blended with a commercially available bisphenol‐A‐based epoxy (EP) in different ratios (PE or PA:EP = 100:40, 100:50 and 100:60 by weight) by using the solution blending technique in xylene. The tensile strength, impact strength, adhesive strength, flexibility, hardness, elongation at break, swelling behaviour and chemical resistance in different media of the films for both the blends have been studied.

Findings

The blending of PE and PA resins of Mesua ferrea L. seed oil with a commercially available bisphenol‐A‐based epoxy (EP) showed very good compatibility of the components as observed by SEM study. The blending also significantly improved the performance characteristics such as drying time, tensile strength, impact strength, adhesive strength, chemical resistance, etc. of the films.

Research limitations/implications

The epoxy resin and the hardener are used of a particular grade of a particular manufacturer. Further, it could be obtained from different sources and of different grades. In addition, the performance characteristics could also be studied to optimise the exact blend ratio.

Practical implications

The method developed provided a simple and practical solution to improve the performance characteristic of polyurethane resin with less than one NCO/OH ratio.

Originality/value

The method for improving the performance characteristics of epoxy modified vegetable oil based polyurethane is something novel and could find numerous applications in surface coatings, adhesive and thin film.

Details

Pigment & Resin Technology, vol. 36 no. 2
Type: Research Article
ISSN: 0369-9420

Keywords

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